For all of three quarters Thursday night in the San Diego County Credit Union Poinsettia Bowl, San Diego State looked as if it might just eke out a win against its bitter rival, BYU.

But the Aztecs (9-4) unraveled in the fourth quarter as BYU’s vaunted defense dug in its heels and stood fast against an SDSU offense that seemed to fade as the night wore on.

Led by linebacker Kyle Van Noy’s electrifying play, the Cougars (8-5) scored two defensive touchdowns in the fourth quarter to pull out a gritty 23-6 win. It was BYU's 15th win over SDSU in the last 17 meetings.

The turning point came with 12:37 remaining in the game, under the most unlikely of circumstances.

After three quarters of exchanging field goals, momentum finally appeared to be in SDSU’s favor. Cornerback King Holder made the crowd roar in approval when he intercepted BYU QB James Lark at the 1 yard line, saving a potential BYU touchdown.

The Aztecs’ offense trotted out, ready to capitalize.

But on the first play from scrimmage, BYU’s Van Noy broke through the Aztecs’ offensive line and pounced on SDSU quarterback Adam Dingwell as he was throwing.

The ball popped out of Dingwell’s hand, and Van Noy recovered the fumble in the end zone.

Officials ruled the play a BYU touchdown, then halted the action for an official review.

From some camera angles on the TV replay, it looked as if Dingwell’s arm could have been moving forward as the ball was knocked out.

Was it a fumble or an incomplete pass?

In hindsight, no one seemed 100 percent sure.

“It happened so fast, from my angle you can’t tell if his arm was going in motion,” Van Noy said.

“I couldn’t tell,” Dingwell supplied. “It was unfortunate. It was a bang-bang play. I have to protect the ball. That can’t happen.”

All that mattered was that the officials upheld the original ruling: touchdown BYU.

That was the beginning of the end for SDSU

Down 10-6, with the clock ticking, the Aztecs’ offense unraveled as they tried to make something happen.

On their very next play, with SDSU deep in its own territory, Dingwell fumbled the snap and BYU’s Jordan Johnson recovered the fumble.

Seventeen seconds after Van Noy’s game-breaking scoring play, the Cougars struck again, with Jamaal Williams scampering into the end zone on a 14-yard touchdown that widened the gap to 16-6.

The final 12 minutes of the game unfolded in a comedy of errors for the Aztecs as Dingwell was sacked and penalized for intentional grounding on one drive, and intercepted by nemesis Van Noy on the next.

Van Noy added insult to injury by running the pick back 17 yards for his second touchdown of the night to give BYU a seemingly insurmountable 23-6 lead.

The Aztecs’ hopes of picking up win No. 10 were completely extinguished by their next drive, when Dingwell threw his third interception of the game with less than five minutes remaining.